Core barrel assembly



Feb. 2, 1954 J. C. STOKES 2,668,037

CORE BARREL ASSEMBLY Filed Oct. 28, 1950 3 Sheets-Sheet l ffy/ff A'/ 23, l '22m 7 Emu 1 Feb. 2, 1954 J. c. s'roKEs 2,668,037

CORE: BARREL ASSEMBLY Filed oct. 28, 1950 3 sheets-sheet 2 doh/7 C. So/fes INVENTOR.

. im )na/Sra! A r (OR/v5 ys Feb. 2, 1954 J. c. sToKEs 2,668,037

CORE BARREL ASSEMBLY v Filed Oct. 28, 1950 3 Sheets-Sheet 3 P7/yr 6 7 l TT INVEN TOR. l M4144,-

/4 TTOHNEKS Daag/ihm I- Patented Feb. 2, 1954 conn BARREL ASSEMBLY John C. Stokes, Houston, Tex., assigner to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application October 28, 1950, Serial No. 192,748

(Cl. Z55-72) Claims.

This invention relates to new and useful improvements in core barrel assemblies.

As is well known, the usual core barrel'assembly ordinarily comprises an outer barrel and an inner barrel, with a core catcher mounted in the lower portion of the inner barrel. The core being cut moves upwardlyinto the inner barrel past the core catcher and when the coring operation is completed, the engagement of the core catcher with the core is depended upon to effect fracturing or breaking 01T the core. Since the core catcher is mounted within the inner barrel, which must of necessity be rotatably connected to the outer barrel, the inner barrel carries the strain of breaking off the core. In the softer formations where breaking off of the core'requir'es a relatively small force, little difficulty is eX- perienced, but in the harder formations the strain occasioned by the breaking of the core may result in damaging the inner core barrel. Further, the usual core barrel assembly requires removal of the inner barrel from the lower end of the outer barrel which means that said inner barrel cannot be removed from the well bore separately from the outer barrel and this is disadvantageous if difficulty is encountered during the coring operation.

It is one object of this invention to provide an improved core barrel assembly which is particularly adapted for use in coring hard formations.

An important object is to provide an improved core barrel assembly wherein the core catcher is so mounted that when the core has been cut and the assembly moved upwardly to break off the ycatcher support slidably mounted on the lower portion of the inner barrel and adapted to support any selected type of core catcher; the construction being such that the catcher functions in a normal manner during the coring operation with a catcher support that may slide toward its upper position relative to the inner barrel, said support automatically moving downwardly into contact with the outer barrel assembly and core bit to transfer the strain of breaking the core to said outer barrel and bit when the assembly is lifted upon completion of the coring operation.

Another object of the invention is to provide a core barrel assembly which is so constructed that the inner barrel may be withdrawn from the upper end of the outer barrel, whereby removal of the core from the barrel at the surface is facilitated and also whereby said inner barrel with catcher and core may be removed from the well bore separately from the outer barrel.

A still further object is to provide a core barrel assembly, of the character described, which is so designed that a safety joint may be connected between the inner barrel and the outer barrel of the assembly to permit separation of thevinner barrel and removal thereof from the well bore independently of said outer barrel.

'I'he construction designed to carry out the invention will vbe hereinafter described together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

Figure 1 is a transverse, vertical sectional view of a core barrel assembly, constructed in accordance with the invention and illustrating the same in fa, position cutting the core,

Figure 2 is an enlarged transverse, sectional view of the lower portion of the assembly,

Figure 3 is a horizontal, cross-sectional view, taken on the line 3 3 of Figure 2,

Figure 4 is a horizontal, cross-sectional view, taken on the line 1 4 of Figure 2,

Figure 5 is a view, similar to Figure 2, illustrating the core-catcher support in position during breaking of the core,

Figure 6 isfa sectional detail showing removal of the core from the inner barrel,

Figure 7 is a transverse sectional view of a modified form of the invention,

Figure 8 is a transverse sectional View of another modication of the invention,

Figure 9 is an enlarged sectional detail of the core catcher support shown in Figure 8, and

Figures 10 and l1 are horizontal, cross-sectional views, taken on the lines I-i Q and l I--I I, respectively, of Figure 8.

In the drawings, the numeral I0 designates an 'outer tubular core barrel which has a core bit Il lconnected to itsl lower end by means of a connecting sub I2. The core bit is formed with la central or axial opening I3 and is illustrated as the usual diamond type of core drilling bit. The central opening I3 in the bit is in axial alignment with an axial opening I4 in the sub I2; an annular inclined or beveled shoulder or seat I5 is formed lwithin the sub I2 at the lower end of the bore of said sub. The major portion of the lower end of the connecting sub i2. 'lower surface of each stop lug V3! is beveled or the bore 12a of the sub is of a larger diameter than the bore lila of the outer core barrel I9 to allow clearance and slush passage (Figure 5).

Adapted to extend axially through the outer core barrel I0 is an inner core receiving barrel i6, and said inner barrel is constructed of a suitable tube or pipe section. The upper end of the inner core receiving barrel has connection with a coupling assembly l1 and by means of the assembly Il the inner core barrel is rotatably mounted within the bore I8 of a safety tool joint I9. The joint is provided with internal shoulders and 2 I, which shoulders function -to-con i'ine the coupling assembly .H against @longitudinal movement with respect to the joint i9, while permitting relative rotation of the joint with respect to the inner barrel i6. A short tube 22 surrounds the upper portion'of 'the lmandrel Vla of the coupling assembly I1 and extends vinto the lower end of an upper connection 23 which couples the safety joint i9 to the drill pipe (not shown). The tube 22 is retained in position by a retaining nut 22a. It ispointed out that any suitable type of rotatable mounting may be einployed for connecting the upper portion of the inner core receiving barrel `Hi to the .joint i9. As will hereinafter appear, the relatively coarse thread l9a of the safety joint I9 could be omitted, anda standard thread substituted for the same. The inner core receiving barrel i5 is axially aligned within the outer core barrel Hl by radial guide wings 24 secured to the upper end of the exterior of said inner barrel and said wings also Vfunction to guide the inner barrel during assembly. Obviously, the guides havean outer diameter which is less than the inner diameter of the outer barrel. The lower end of the `barrel has a tubular sleeve member 25 threaded thereon,

`and this sleeve is also provided with centering wings 26 which maintain axial alignment of the lower end of the inner barrel. The lower lportion of the sleeve member 25 is'enlarged in diameter and is disposed within the bore 12d of the connecting sub l2; this enlarged lower portion` of the member is formed withlongitudinally y extending slits which are spaced radially therearound to provide a plurality of resilient latching or stop arms 2. The inherent resiliency of the material-of which the-arms 21 are constructed normally maintains said arms in the position `shown in Figure 2, but obviously said'arms 'may be swung outwardly so that their lower ends may vbe spread in a radial direction. Each arm 21 is formed with an inwardly directed lug 28 at its extreme lower end.

An annular core-catcher support 29 ismounted within the lower portion of the sleeve member 25 and is axially slidable within limits within the Vlatch arms 21. The support 29 is the form of a collar and upward movement of this supporting collar .is restricted by an internal shoulder 39 which is formed within the sleeve member 25 between the upper body portion of said sleeve and the latch or stop arms 21. Downward movement of the core-catcher support or collar 29 is limited by the engagement of a Vplurality of lugs 3| formed on the lower end of said collar with the inclined seat l5 provided Within The inclined as indicated at 3m and this inclination is preferably complementary to the inclination of the seating surface l5. Complete .displacement or downward movement of the c orecatcher support or collar 29 from the sleevemember 25, when said sleeve member and inner core barrel are outside of the outer core barrel, is prevented by the engagement of an external shoulder 32 formed on the support or collar 29 with the inwardly directed lugs 28 of the stop arms 21. Thus, when the inner core barrel is outside of the outer core barrel, downward move- =ment-of the support .or collar 2S and "displacement of this element from the sleeve member 25 is prevented by said shoulder 32 engaging the inwardly directed lugs 28 of the stop arms 2l.

The bore 29a of the annular core-catcher support 'or collar 29 is tapered or inclined, as is .clearly illustrated in Figure 2, and this tapered surface forms .aseat for the usual split sleevetype core ycatcher 33. It will be evident that as. the core catcher moves downwardly along the tapered seat "29a, its inner diameter will be reduced to rmly engage a core which might be extending therethrough. The operation of the core catcher is usualand any suitable well known core catcher maybe mounted within the support ,29. Upward displacement of the core catcher 33 from the support A29 is prevented by kmeans of a snap ring 34 which is mounted within the extreme upper end of the support or collar 29.

In the operation-of the assembly, the partslare assembled as shown in Figure land in such position the inner core barrel I6 is rotatably mounted within the safety joint i9. The relatively coarse threads i9a of the safety joint are coupled to the upper end of the outer-core barrel l0 and since the upper end of the safety `ioint has connection through the upperconnection 23 with the drill pipe (not shown) it will be yevident that a rotation of the drill pipe will impart a rotation to the outer core barrel IB and to the core drill H mounted at its lower end. As the core A is cut, it mayenter the lower end of the inner core receiving barrel I6 in the usual manner, and said inner core barrel may remain stationary las the outer barrel and drill pipe are rotated.

As the coring operation proceeds, the frictional engagement of the 4core A moving upwardly through the opening I3 Vin the bit and then upwardly through the core catcher support 29 and core catcher 33 will cause the core catcher Lto ride upwardly within the support. Atthe same time, the support v2E) will tend to be lifted to the upperposition as shown in Figure 2, with the upper end of the support engaging the shoulder 30. At this time, the limiting or stop lugs V3| .at the lower end of the support or collar 29 are spaced upwardly above the inclined seating survface l5 within the lower portion of the connectingrsub I2.

When the coring operation is complete, rotation o the assembly is halted and an upward pull is takenfon the drill pipe which tends to lmove the entireassembly upwardly. Because the core catcher 33 is in frictional engagement with the core A, which is at this time still attached to the formation, the upward movement of the assembly will tend to move the core catcher 33 downwardly along the tapered bore 29a of the core catcher support 29. At the same time, the corecatcher vsupport 29 will more downwardly until its -stop or limiting lugs 3i engages the inclined seat i5 within the connecting sub, as shown in Figure 5. When this occurs, the strain which will beplaced on the core catcher as a continued upward pull is taken on the drill pipe, is transmitted directly to the core-catcher support 29 and through the support to the connecting sub l2. The strain of breaking oi the core is therefore the arms 21.

directly transferred to the bit II and outer core barrel I0, which parts are well capable of withstanding this strain because they are connected directly to the drill pipe. It is noted that because the core-catcher support 29 engages the .seat I5 the inner core receiving barrel I6 is relieved of any possible strain which may be occay sioned when the core is broken off. After breaking of the core, the entire assembly may be brought to the surface and the core catcher 33 will, of course, retain the core within the inner core receiving barrel in the usual manner.

After the assembly is brought to the surface,

vthe inner barrel I6 may be removed from the outer barrel either by uncoupling the coarse threads I 9a of the safety joint I9 to permit withdrawal of the inner barrel from the upper end of ,the outer barrel, or if desired the drill bit and sub may be removed from the lower end of the outer barrel so that the inner barrel may be withdrawn from the bottom of the outer barrel. In eiecting the withdrawal from the bottom or lower end of the outer barrel the upper connection with the upper end of the safety joint I9 would, of course, have to be broken and the ynut 22a and tube 22 removed from the inner barrel. The structure thus permits removal of the inner barrel from either the upper or the lower end, as desired, of the outer core barrel.

For permitting a removal of the core from the inner barrel, it is necessary that .the stop arms 21 be spread to allow removal of the core-catcher `support 29 and the core catcher 33 from the sleeve member 25. Spreading of the arms 21 may be accomplished in any suitable manner so as to per- .mit the shoulder 32 on the core-catcher support 29 to clear the lugs 23, after which removal of the core-catcher support, together with the core catcher therein, from between said is effected. To facilitate the spreading of the stop arms 21, a removal tool T illustrated in Figure 6 may be provided. This tool comprises a base 35 having an upstanding collar 3S secured thereto. The lower portion of the bore of the collar 36 has an inclined seat 31 which is disposed at an inclination complementary to the inclination of the lower end of the limiting or stop lugs SI of the core-catcher support. The upper edge of ythe collar is beveled inwardly at 33, whereby said upper end may be engaged beneath the lower ends of the stop arms 21.

In using the tool T, the same is merely slid around the lower end of the coreeoatcher support 29 after said support and the inner 'barrel have been removed from the outer barrel, and the upper beveled end 38 of the collar 36 will engage beneath the arms 21 to move said arms radially outwardly. The collar 36 continues its inward movement on the core-catcher support until its inner end strikes the external shoulder 32 on said support and when this occurs the tool T and the support 29 may be removed from between Of course, the core catcher 33 within the support is still gripping the core and this will permit a removal of the core A from the inner core receiving barrel I. Although the tool T illustrated in Figure 6 has been found sat' isfactory to effect a displacement of the corecatcher support from within the latch arms 2'! of the sleeve member 25, any other desired method for spreading the latch arms to permit such displacement may be employed.

As has been noted, the drill pipe is connected to the outer barrel IU through the safety joint I9. There may be instances where the drill bit and outer barrel I0 may become stuck within the well bore during the coring operation, and if this occurs, the provision of the safety joint I9 Will permit the drill pipe to be disconnected from the outer barrel. The inner barrel I6 is secured within the coupling I9, and this coupling has connection through regular threads with the drill pipe 23. It also has connection through the safety joint threads I9a with the outer barrel. The thread connection I9a is a coarser thread and when the drill pipe is turned in a left hand direction an unsorewingV of the safety joint threads I9a will occur before unscrewing of the regular threads will take place. Therefore, if the outer barrel becomes stuck a rotation in a left hand direction of the drill pipe will break the connection at the threads Illa. Because the inner core receiving barrel I6 has its upper end connected with the safety joint I3, removal of the drill pipe after disconnection from the outer barrel Will allow the inner barrel to be withdrawn upwardly with said drill pipe. This is a decided advantage because subsequent fishing operations in order to remove thestuck outer barrel will be greatly simplified when the inner barrel has been previously removed therefrom. The structure makes it possible to withdraw the inner barrel upwardly from the upper end of the outer barrel, and it is this arrangement which facilitates the use of a safety joint connection between the drill pipe and the outer barrel. Of course, it is to be understood that the invention is not to be limited to the use of the safety joint Iii because in those cases where it is not likely that the bit and outer barrel may become stuck, standard threaded connections may be used; however, the use of the safety joint I9 is of added protection in the event that sticking of the outer barrel should occur.

In Figure 7 a modied form of the invention is shown, and in this form the means which prevents complete displacement of the core catcher support from the lower end of the inner core barrel is varied. Referring to Figure '1, a core catcher support 28h is provided with an internal shoulder 29C at its upper end and said shoulder confines the split core catcher 33 against upward displacement from said support. The upper portion of the support 2910 is extended upwardly and telescopes a sleeve member 2M which is secured to and projects from the lower end of the inner core barrel I6. A connection between the upper `portion of the support 2917 and the sleeve 29d is efe fected by slots 23e formed in the support and pins 291c provided on the sleeve. It isA evident that the pin and slot connection allows telescoping movement between the coreecatcher support A29h and the sleeve 29d carried by the inner core barrel while preventing displacement of the support from said sleeve. The operation of this form of the device is identical to that of the iirst form heretofore described. v

In Figures 1 to 6 the core catcher support is illustrated as employed with the usual diamond core bit,'which, as is well known, is employed in extremely hard formations. It may be desirable I in certain instances to employ the improved corecatcher support with an ordinary roller or soft formation type bit and in Figures 8 to ll, such an arrangement is shown.

Referring to Figure 8, the outer core barrel I0 7 tothesleere 2.5 of theiirst :form is connected t ,the 'lower end of the inner core-receiving barrel i6. The lowerportion of the bore of the sleeve 4.3 is slightly enlarged to provide an internal shoulder 44 within the bore of said sleeve. An annular stop element 45 is threaded onto the lower end of the sleeve 43 and includes a collar portion 4G at its upper end and extends downwardly within the bore of the bit above the Shoulder 42. A core-catcher support 48 in the form of a collar is slidable within the stop element 45 `and is provided with an external shoulder 49 which co-acts with an inwardly directed shoulder 5) on the element 45 to prevent complete displacement of the support 48 from said stop element. A core catcher 5l which is shown as of the spring linger type is disposed within the sleeve 43 and has its lower end extending into the core-catcher support 48. The

`lower portions of the spring arms of the core catcher 5l are inclined to co-act with the tapered bore 4taJ of the support 48 so that upon downward movement the spring lingers of the catcher are more rmly engaged With the core extending therethrough. The lower end of the collar or support 48 is adapted to engage the internal shoulder 42 within the drill bit 40.

The operation of this form of the invention is substantially the same as the rst form. As the core is cut and moves upwardly through the opening 4l in the bit and then through the annular core-catcher support 481 and core catcher 5l, said core will tend to move the core catcher to its uppermost position engaging the restraining shoulder 44 within the sleeve 43. The support 48 for the core catcher may ride upwardly within the stop element 45 and thus, the coring operation proceeds in a normal manner.

When coring is complete and it is desired to break o the core, an upward pull Yon the drill pipe will tend to move the outer barrel and drill bit upwardly with respect to the core. Such upward movement will cause the shoulder 42 to engage the core-catcher support or collar 48 and will cause the collar to co-act with the lower ends of the core catcher to-rmly grip the core. Subsequent upward pull on the drill pipe will transmit the strain of breaking 01T the core directly from the core through the core catcher and then through the core-catcher support 4S to the bit 4D. Since the bit is attached to the outer core barrel l0 and then to the drill pipe, it is obvious that the drill pipe Vand outer barrel are -well able to take the strain of breaking off a hardformation core. As in the first form of the invention, the inner core receiving barrel i6 is relieved of any of the strain ofbreaking off said core.

It is apparent that in the lform shown in Figures 8 to 11, the safety joint i9 may be employed so as to permit removal of the inner core receiving barrel from the outer barrel through the upper end of said outer barrel, whereby in the event of sticking of the outer barrel and bit, the inner core receiving barrel may be removed with the drill pipe. Also, in this form of the invention, removal of the inner core receiving barrel maybe effected from the lower end of the outer barrel by merely removing the drill bit 40 from the outer barrel and removing nut 22a. and sleeve 2.2 from inner barrel. In all forms of the invention, the strain imposed upon the assembly due to breaking off of the hard formation core is transferred from the inner barrel directly to the drill bit and outer barrel, which latter parts 8 are more able to withstand'said ystrain thdlifthe inner barrel.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the claims, without departing from the spirit of the invention.

Having described the invention, I claim:

1. A core barrel assembly including, an outer barrel having an internal seat within its lower portion, an inner barrel Within the outer barrel and having its lower end terminating above the seat, a sleeve member secured to the lower end of the inner barreland having radially expansible elements on its lower end, an annular core catcher support slidable within the sleeve and conned against complete displacement downwardly therefrom by said radially expansible elements, the lower end of the support being engageable with the seat within the outer barrel prior to reaching its limit of downward movement relative to the expansible elements, and a core catcher mounted within the annular support.

2. A core barrel assembly as set forth in claim 1, wherein the annular support has a tapered bore and. wherein portions of the external surface of the core catcher are also tapered, whereby downward movement of the catcher within the bore urges the catcher into tight engagement with a core extending therethrough and also sets up a frictional engagement between the catcher and its support.

3. As a sub-combination in a core barrel assembly, a core catcher unit comprising, a tubular sleeve having an internal shoulder therein and having radially expansible retaining elements ex'- tending downwardly below the shoulder, a corecatcher support slidable axially within the sleeve and having its inward movement Vlimited by the shoulder and its outward movement limited by the retaining elements, and a core catcher mounted within the support.

4. The sub-combination set forth in claim v3, wherein the bore of the support is tapered and portions of the external surface of the core catcher are also tapered.

5,. A core barrel assembly comprising, an outer barrel having an internal abutment at the lower end of its bore, an inner core-receiving barrel extending within the outer barrel and having its lower end terminating above the internal abutment, a core catcher support extending upwardly above the lower end of the inner barrel havllng its downward movement limited by the .enf

gagement with the abutment, a lateral shoulder on said core catcher support, a lateral projection on said core-receiving barrel disposed below said lateral shoulder and being movable upwardly into engagement with said shoulder upon an yupward movement of said core-receiving barrel relative to said support to thereby prevent separation of said support from said inner core-receiving barrel when said inner barrel is removed from said outer barrel, and a core catcher within the support and adapted to engage a core extending upn wardly into the inner barrel, said catcher functioning to move the support downwardly into engagement with the abutment when the barrel assembly is moved upwardly relative -to the core which is engagedby said core catcher, said lateral projection being spaced sufficiently below said lateral shoulder so that when said support is moved downwardly by said catcher the con-tact of said support with said internal abutment prevents engagement of said projection with said shoulder.

6. The core barrel assembly as set forth in claim 5, wherein the bore of the core catcher support is tapered downwardly and inwardly and portions of the outer surface of the core catcher are also tapered downwardly and inwardly, whereby downward movement of the catcher relative to the support urges the catcher into tighter gripping engagement with the core and at the same time sets up a frictional contact between the catcher and the support to assure relative downward movement of the support with respect to the limiting abutment.

7. The core barrel as set forth in claim 5, wherein the outer barrel is connected to a drill pipe by means of a safety joint coupling and also wherein the inner barrel is attached to the coupling, whereby disconnection of said coupling from the outer barrel permits removal of the inner barrel upwardly from said outer barrel. t

8. A core barrel assembly as set forth in claim 5, together with a pin and slot connection between the inner barrel and the core catcher support for permitting limited telescoping movement of the support relative to the barrel, while preventing complete separation of the support from said barrel.

9. A core barrel assembly including, an outer barrel, a safety joint coupling attached to the lower end of the drill pipe adapted to be coupled to the outer barrel, an inner core-receiving barrel having its upper end extending axially within the safety joint coupling, and a rotatable connection attaching said inner barrel to said coupling whereby said inner barrel may remain stationary when engaged by a core while the outer barrel and coupling are rotated, the safety coupling being releasable from the outer barrel while maintaining the connection between the coupling and the inner barrel whereby a core can be retrieved in the inner barrel even though the outer barrel is stuck in a well bore.

10. The core barrel assembly set forth in claim 9, wherein the safety joint coupling has an annular ledge of increased diameter as compared to its bore, said inner core-receiving barrel extending through the bore of the coupling and projecting above said annular ledge, and an annular flange on the external surface of said inner barrel and of larger diameter than the bore of the coupling and resting upon said annular ledge whereby the inner barrel is prevented from separating from the coupling upon upward movement of the coupling after disconnection from the outer barrel.

JOHN C. STOKES.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 473,910 Bullock May 3, 1892 1,588,367 Holmgreen June 8, 1926 2,103,611 Catland et al. Dec. 28, 1937 2,381,844 Stokes Aug. 7, 1945 2,490,512 Deely Dec. 6, 1949 2,522,399 Pickard Sept. 12, 1950` A FOREIGN PATENTS Number Country Date 618,444 Germany Sept. 11, 1935 

